Matrix user forums

We are using the Eblocks multiprogrammer board in conjunction with the Eblocks EB083 combo board. We are using assembly for PIC micros software and tutorials.

When we get onto the tutorials which use the 7 segment displays (Section 2 of the tutorials) these do not work correctly on the combo board. For example tutorial 2.6 (I think) which counts in decimal on the 7 segment display we can only get the display to illuminate if we press one of the port A buttons. From memory I think that it is buttons A2 to A5 which if pressed activate each of the 7 segment displays.

The earlier tutorials which just illuminate the LEDs on port B appear to work fine. I haven't tried accessing the LCD display. I assume that if we know how the combo board is configured we can modify the tutorials to get them to work.

Would you expect these issues when using the combo board and is there a software update which allows the tutorials to work without modification. Originally we used the V2 hardware with the assembly for PIC micros software but have now upgraded to Eblocks, the multiprogrammer plus the combo board being the simplest and most cost effective way of replacing the V2 hardware.

Regards, Keith Emerson

Hi Keith,

Are you still using the target microcontroller you were using in the v2 dev board? The hardware connections are identical so the course as is should work with the chip it was designed for.

If you've moved to the 16F88 device then for PORTA there is an ANSEL register which we added to later versions of the course when updating to the new chip. The ANSEL register basically allows the port to be configured into digital mode as by default it's in analogue mode. I think you have to clear the register to put it into digital mode.

Hi,

The ANSEL register is cleared as part of the tutorial 25. The problem seems to be that Port A is not putting power onto the anodes of the display chips. I'm pretty sure that the combo board will not work "fully" with all tutorials without some additional modifications to the tutorial programmes. I know that the combo boards are relat5ively new but I'm a bit surprised if no one has contacted you regarding problems.

Thanks for any assistance

Keith

I don't know if this helps you track down the problem.

Tutorial 26 works fine with the E blocks LED 7 segment module. i.e. two digits counting up in decimal.

When using the combo board both digits show the same information which changes with the count. The multiplexing of the display is not working correctly. on some of the counts some of the segments have reduced brightness
whilst some are full brilliance. Again I assume this is due to the multiplexing of the display
Thanks,

Keith

Hi Keith,

Thanks for the info, I'm converting the Assembler course over the next couple of days so I will let you know how I get on when I get to the multiplexing bit, might be that the LEDs are not on for long enough with the new faster crystal.

Hi,

It does seem to be some sort of timing issue. The individual segment displays are not fully off when the data is applied to
port B resulting in a residual output to the un-selected digits. This doesn't happen with the stand-alone LED display but this doesn't have the additional LEDs etc which the COMBO board has.

Thanks, Keith

By the way the LCD display seems to work fine.

Keith Emerson